feat: GPUI desktop port foundation

- scene crate: full project/scene/element model, serde round-trip
  proven against the web SerializedProject shape
- transfer crate: .ocp zip container, cross-compat with web fflate
  archives proven in both directions
- storage crate: filesystem project store replacing IndexedDB,
  .ocp import/export
- media crate: ffmpeg-next 8 decoder (frames, audio, thumbnails,
  waveform summaries)
- playback crate: wall-clock anchored, frame-rounded playback clock
- gpu crate: native texture readback; compositor renders headless
  offscreen on Vulkan (spike test)
- flake devshell: rust toolchain, GPUI native deps, ffmpeg dev,
  bindgen clang args; GPUI hello-world builds
- port plan in notes/gpui-port.md

3 files changed, 151 insertions, 0 deletions

diff --git a/rust/crates/transfer/tests/container.rs b/rust/crates/transfer/tests/container.rs
new file mode 100644
index 00000000..f05ef329
--- /dev/null
+++ b/rust/crates/transfer/tests/container.rs
@@ -0,0 +1,95 @@
+use std::io::Write as _;
+
+use transfer::*;
+
+fn sample_media() -> Vec<ArchiveMediaInput> {
+    vec![
+        ArchiveMediaInput {
+            metadata: ArchivedMediaMetadata {
+                id: "asset-1".into(),
+                name: "clip one.mp4".into(),
+                media_type: "video".into(),
+                file_type: "video/mp4".into(),
+                last_modified: 1_753_000_000_000.0,
+                width: Some(1920.0),
+                height: Some(1080.0),
+                duration: Some(12.5),
+                ephemeral: None,
+                thumbnail_url: None,
+            },
+            data: vec![1, 2, 3, 4],
+        },
+        ArchiveMediaInput {
+            metadata: ArchivedMediaMetadata {
+                id: "asset-2".into(),
+                name: ".hidden".into(),
+                media_type: "audio".into(),
+                file_type: "audio/wav".into(),
+                last_modified: 1_753_000_000_001.0,
+                width: None,
+                height: None,
+                duration: None,
+                ephemeral: Some(true),
+                thumbnail_url: None,
+            },
+            data: vec![5, 6, 7],
+        },
+    ]
+}
+
+#[test]
+fn sanitize_matches_web_rules() {
+    assert_eq!(sanitize_file_name("clip one.mp4"), "clip_one.mp4");
+    assert_eq!(sanitize_file_name(".."), "file");
+    assert_eq!(sanitize_file_name("...weird..name.."), "weird..name..");
+    assert_eq!(sanitize_file_name("a  b"), "a_b");
+    assert_eq!(sanitize_file_name("   "), "file");
+    assert_eq!(sanitize_file_name("caf\u{00e9}.mov"), "caf_.mov");
+}
+
+#[test]
+fn archive_round_trip() {
+    let project_json = r#"{"version":7,"metadata":{"id":"p1"}}"#;
+    let archive = build_project_archive(project_json, sample_media()).expect("build");
+    let parsed = parse_project_archive(&archive).expect("parse");
+
+    assert_eq!(
+        parsed.project.get("version").and_then(|v| v.as_u64()),
+        Some(7)
+    );
+    assert_eq!(parsed.media.len(), 2);
+    assert_eq!(parsed.media[0].entry, "media/asset-1-clip_one.mp4");
+    assert_eq!(parsed.media[1].entry, "media/asset-2-hidden");
+    assert_eq!(
+        parsed.read_media_data("media/asset-1-clip_one.mp4").unwrap(),
+        &[1, 2, 3, 4]
+    );
+    assert_eq!(parsed.read_media_data("media/asset-2-hidden").unwrap(), &[5, 6, 7]);
+}
+
+#[test]
+fn archive_without_media_is_valid() {
+    let archive = build_project_archive("{}", Vec::new()).expect("build");
+    let parsed = parse_project_archive(&archive).expect("parse");
+    assert!(parsed.media.is_empty());
+}
+
+#[test]
+fn rejects_garbage() {
+    let error = parse_project_archive(b"not a zip").unwrap_err();
+    assert!(error.to_string().contains("unreadable zip file"));
+}
+
+#[test]
+fn rejects_missing_project_json() {
+    let mut cursor = std::io::Cursor::new(Vec::new());
+    {
+        let mut writer = zip::ZipWriter::new(&mut cursor);
+        let options: zip::write::SimpleFileOptions = Default::default();
+        writer.start_file("other.txt", options).unwrap();
+        writer.write_all(b"hi").unwrap();
+        writer.finish().unwrap();
+    }
+    let error = parse_project_archive(&cursor.into_inner()).unwrap_err();
+    assert!(error.to_string().contains("project.json is missing"));
+}
diff --git a/rust/crates/transfer/tests/cross_compat.rs b/rust/crates/transfer/tests/cross_compat.rs
new file mode 100644
index 00000000..02e53ac6
--- /dev/null
+++ b/rust/crates/transfer/tests/cross_compat.rs
@@ -0,0 +1,56 @@
+use transfer::*;
+
+#[test]
+fn parses_web_built_archive() {
+    let archive = std::fs::read(concat!(env!("CARGO_MANIFEST_DIR"), "/tests/fixtures/web-built.ocp"))
+        .expect("web-built fixture");
+    let parsed = parse_project_archive(&archive).expect("parse web archive");
+
+    assert_eq!(
+        parsed
+            .project
+            .get("nested")
+            .and_then(|n| n.get("value"))
+            .and_then(|v| v.as_u64()),
+        Some(42)
+    );
+    assert_eq!(parsed.media.len(), 1);
+    assert_eq!(parsed.media[0].entry, "media/web-asset-web_clip.mov");
+    assert_eq!(parsed.media[0].metadata.media_type, "video");
+    assert_eq!(parsed.media[0].metadata.width, Some(1280.0));
+    assert_eq!(
+        parsed.read_media_data("media/web-asset-web_clip.mov").unwrap(),
+        &[9, 8, 7, 6]
+    );
+}
+
+#[test]
+fn writes_rust_built_archive_for_web_parse() {
+    let archive = build_project_archive(
+        r#"{"version":7,"metadata":{"id":"rust-built"}}"#,
+        vec![ArchiveMediaInput {
+            metadata: ArchivedMediaMetadata {
+                id: "rust-asset".into(),
+                name: "rust audio.mp3".into(),
+                media_type: "audio".into(),
+                file_type: "audio/mpeg".into(),
+                last_modified: 1_753_000_000_000.0,
+                width: None,
+                height: None,
+                duration: Some(1.5),
+                ephemeral: None,
+                thumbnail_url: None,
+            },
+            data: vec![4, 3, 2, 1],
+        }],
+    )
+    .expect("build");
+    let parsed = parse_project_archive(&archive).expect("re-parse");
+    assert_eq!(parsed.media[0].entry, "media/rust-asset-rust_audio.mp3");
+    assert_eq!(
+        parsed
+            .read_media_data("media/rust-asset-rust_audio.mp3")
+            .unwrap(),
+        &[4, 3, 2, 1]
+    );
+}
diff --git a/rust/crates/transfer/tests/fixtures/web-built.ocp b/rust/crates/transfer/tests/fixtures/web-built.ocp
new file mode 100644
index 00000000..473897de
--- /dev/null
+++ b/rust/crates/transfer/tests/fixtures/web-built.ocp